How to use this calculator
- Enter biological input application costs.
- Establish a gross margin: grain price, yield and expected change in income (%) due to biological input use.
- Limiting factors: only pH has been entered to date (If you enter a pH above 6, then the program will show no benefit / saving to liming). Enter a pH above 6 if you know the product you are trialing does not ameliorate acid soils.
Additional Factors (changes to nutrient/lime requirements etc.):
- Enter any expected changes in proposed N, P, K and lime requirements. (This section is very subjective and designed for testing ideas, not to be used to provide a prescription.)
Impact of biological inputs:
- This measures how much of the improvement in profit can be expected to flow after year 1, with options to test when re-application might be desirable. The second part of the calculation is to make judgement on how many years it is feasible to apply the altered level of nutrients. The base assumptions for the model assume a cost saving on inputs of $8.35/ha for 4 years after the application of biological input. Please change this to suit your own property.
- If you believe biological input effects are nil in any of the ten out-years, enter a “0%” in the years you believe there is no benefit, and uncheck the column asking whether to apply input changes for those years.
- Summary – This deducts the cost of the treatment from the benefit expected over five years to assess whether the treatment is considered worth pursuing base on the estimates you have made.